Arogenate dehydrogenases may utilize NAD+ (EC 1.3.1.43), NADP+ (EC 1.3.1.78), or both (EC 1.3.1.79). NAD+-specific enzymes have been reported from some bacteria [2] and plants [3]. Some enzymes also possess the activity of EC 1.3.1.12, prephenate dehydrogenase.